The present invention relates to a connecting device particularly for eyeglasses.
Said eyeglasses can be constituted by a front, formed for example monolithically, which forms two eyewires which accommodate lenses and are connected by means of a bridge, said front is associated, at its ends, with hinges which are in turn connected to temples.
As an alternative, eyeglasses are known which are constituted by a front formed by an arched element provided with a single longitudinal seat for the snap insertion of the upper perimetric edge of a single lens or of a pair of lenses if an intermediate bridge for connecting the eyewires is still present.
As regards the hinges, they are usually constituted by two mutually rotatably associated elements whose free ends are associated by pressing or are embedded for example in the temple and in the front.
As an alternative, said two elements are formed or obtained directly at the ends of said temples and said front.
Eyeglasses are also known which have metallic components and in which it is known to perform welds, by applying heat or ultrasound, in order to mutually connect the two elements that constitute the hinge.
If the eyeglasses are made of plastics, it is known to mutually glue the components and it is also known to obtain the hinges from the mold.
Finally, it is also known to mutually connect two components of the hinge by riveting them.
However, manufacturing these conventional eyeglasses entails high production costs due to the processes required, to the particular machines and to the special molds meant to manufacture them.
Another problem that is felt is the provision of, for example, the extrawide opening of the temple and therefore the possibility to arrange said temple temporarily at an angle of more than 90.degree. with respect to the front, so as to adapt to the shape of the temples of the user or allow to put the eyeglasses on optimally.
Italian patent application no. PD93A000244 of Dec. 17, 1993, is known as a partial solution to these drawbacks, which discloses an elastic hinge for eyeglasses of the type which comprises, at the end of a temple, an elongated hollow body with a flat end, said body containing an elastic means which is arranged between the head of a pivot which passes axially through it and a contrast element which is locked in said body, said pivot passing through said contrast element and engaging a first hinge element to which a second hinge element is pivoted which is fixed to the front of the eyeglasses and has a polygonal profile, one side of which rests on the flat end of said hollow body, said hinge being characterized in that said contrast element comprises two diametrically mutually opposite flexible axial tabs, respective external raised portions of which are accommodated in suitable seats of said hollow body in a non-deformed configuration with them after insertion in said hollow body.
This solution, however, has some drawbacks, including structural complexity, a large number of components, the need to assemble said components, and ultimately high manufacturing costs.
Italian patent application no. UD94A000124 of Jul. 14, 1994 is also known which discloses an elastic hinge for connecting an earpiece and a front of eyeglasses; said hinge is essentially constituted by a support and a cover between which a temple and an insert are radially pivoted by means of suitable screws; said insert is then welded to the front.
Coaxially to one of said screws, arranged at right angles to the longitudinal axis of the insert and of the temple, there is a spring, one end of which cooperates with a pusher tooth which protrudes axially with respect to the temple.
This solution, too, has the above mentioned drawbacks.
Italian patent application no. UD93A000251 of Dec. 17, 1993 is also known which discloses a hinge for connecting the earpieces and frames which has pivot means for connection to cam means and in which the earpiece has at least elastic contrast means of the cylinder type as well as seat means.
In said hinge, the characteristic consists of the fact that the cylinder-type elastic contrast means have, in an upward region, an inclined flat profile with a lateral extension shaped like a retention tooth and that the cam means associated with the frames have two inclined-plane faces which are angled with respect to each other and to the plane that contains the longitudinal sliding axis of said cylinder.
This solution, too, has the above mentioned drawbacks, with the addition that the interaction of the cam with the inclined surface entails friction and sliding problems which can cause seizing.